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The Effect of Osmo and Hormone Priming on Germination and Seed Reserve Utilization of Millet Seeds under Drought Stress

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Original Text Copyright © 2014 by Asadi Aghbolaghi and Sedghi

ORIGINAL ARTICLE

The Effect of Osmo and Hormone Priming on Germination and

Seed Reserve Utilization of Millet Seeds under Drought Stress

Maasoumeh Asadi Aghbolaghi

1

*, Mohammad Sedghi

2

1

M.Sc. of Seed Science and Technology, Faculty of Agricultural Sciences, University of Mohaghegh Ardabili. Ardabil, Iran.

2

Assoc. Professor, Department of Agronomy and Plant Breeding, Faculty of Agricultural Sciences, University of Mohaghegh Ardabili. Ardabil, Iran.

*E-Mail:

Asadi.m66@gmail.com

Received October 21, 2013

The objective of this research was to evaluate the effect of seed priming with osmo and hormone priming on growth and seed reserve utilization of millet seeds under drought stress. Treatments were combinations of 4 levels of drought stress (0, -4, -8 and -12 bar) and 3 levels of seed priming and control with 3 replications. Results showed that with increase in drought stress, germination components such as germination percentage, germination index, mean time to germination, normal seedling percentage, seedling length, seedling dry weight, weight of utilized (mobilized) seed and seed reserve utilization efficiency decreased, but seed priming showed lower reduction. The highest germination characteristics and seed reserve utilization was obtained by priming in control conditions. It is concluded that priming results in improvement in germination components of millet in drought stress conditions.

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ORIGINAL ARTICLE

The Effect of Osmo and Hormone Priming on Germination and

Seed Reserve Utilization of Millet Seeds under Drought Stress

Maasoumeh Asadi Aghbolaghi

1

*, Mohammad Sedghi

2

1

M.Sc. of Seed Science and Technology, Faculty of Agricultural Sciences, University of Mohaghegh Ardabili. Ardabil, Iran.

2 Assoc. Professor, Department of Agronomy and Plant Breeding, Faculty of Agricultural Sciences,

University of Mohaghegh Ardabili. Ardabil, Iran.

*E-Mail:

Asadi.m66@gmail.com

Received October 21, 2013

The objective of this research was to evaluate the effect of seed priming with osmo and hormone priming on growth and seed reserve utilization of millet seeds under drought stress. Treatments were combinations of 4 levels of drought stress (0, -4, -8 and -12 bar) and 3 levels of seed priming and control with 3 replications. Results showed that with increase in drought stress, germination components such as germination percentage, germination index, mean time to germination, normal seedling percentage, seedling length, seedling dry weight, weight of utilized (mobilized) seed and seed reserve utilization efficiency decreased, but seed priming showed lower reduction. The highest germination characteristics and seed reserve utilization was obtained by priming in control conditions. It is concluded that priming results in improvement in germination components of millet in drought stress conditions.

Key words: Millet seed, Priming, drought stress, Germination characteristics, Seed reserve utilization.

Seed germination is usually the most critical stage in life cycle successful crop production (Almansouri et al., 2001). Drought stress has become a critical problem worldwide due to its dramatic effects on plant physiology and performance.

Drought stress delays the onset stage of germination, reduces the rate and increases the dispersion of germination characteristics, resulting in reduced plant growth and final crop yield (Anari et al., 2012). Also Rouhi et al. (2011) reported that increases drought stress lead to growth reduction.

Ansari and Sharif Zadeh, (2012) reported that stress conditions lead to reduction of growth and plant developments.

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germination indexes under stress conditions (Ansari et al., 2013; Rouhi et al., 2011). Seed priming techniques have been used to increase germination, improve germination uniformity, improve seedling establishment and stimulate vegetative growth in more field crops (Iqbal and Ashraf, 2007; Soltani et al., 2006; Kaya et al, 2006; Kaur et al, 2002; Ansari et al., 2012) under stressed conditions. In monocotyledon plants like wheat (Soltani et al., 2006) and mountain rye (Ansari et al., 2012), gibberellic acid after synthesis in the scutellum migrates in to the aleurone layer. The heterotrophic seedling growth (mg per seedling) could be quantitatively described as the product of the following two components: the weight of mobilized seed reserve (WMSR; mg per seed), and the conversion efficiency of mobilized seed reserve to seedling tissue (mg mg-1) (Soltani et al., 2006; Ansari et al., 2012). Therefore, this experimental aimed to evaluate the effect of priming on seed reserve utilization of millet seeds under drought stress.

MATERIALS AND METHODS

The study was conducted in the Faculty of Agricultural Sciences, University of Mohaghegh Ardabili. Ardabil, Iran.

Drought stress at osmotic potentials of 0 (as control), - 4, -8 and -12 bar were adjusted using PEG 6000 before the start of the experiment.

For osmo-priming, seeds were immersed in density of -10 bar PEG 6000 for 15 h at 10°C and for hormone priming, seeds immersed in salicylic acid in density 50 ppm for 15 h at 10°C under dark conditions. Then, the seeds were rinsed with distilled water three times. The treated seeds were surface-dried to match their original moisture content at 15°C for 24 h (Ansari et al., 2012).

Seeds were germinated in 9 cm petri dishes with two Whatman No. 1 filter papers moistened with the appropriate solutions or distilled water for 0 MPa. Fifty seeds per dish were used for each treatment. Seeds were incubated in the dark at 25 ± 1 ◦C in an incubator for 7 days. Three replicates of 50 seeds were weighed (W1), dried at 104◦C for 24 h and then reweighed (W2). Seed water content was calculated as [(W1−W2)/W2]. The initial seed dry weight was calculated using the data for seed water content and W1. After, test time expiration, germination percentage. Also, after 7 days, oven-dried weight of seedlings was determined. The weight of utilized (mobilized) seed reserve was calculated as the dry weight of the original seed minus the dry weight of the seed remnant. Seed reserve utilization efficiency was estimated by dividing seedling dry weight by the utilized seed reserve (Soltani et al., 2006; Ansari et al., 2012).

The experimental design was two factors factorial (seed treatment × drought stress) arranged in a completely randomized design with three replicates. All data were analyzed statistically by analysis of variance using MSTAT-C software. Mean comparisons were performed using an ANOVA protected least significant difference (Duncan) (P < 0.01) test.

RESULTS AND DISCUSSION

Analyze of variance for priming showed that Treatment × Drought stress interaction was significantly (P < 0.01) for all traits (Data not shown).

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conditions. Also, results showed that the highest germination index (Fig 2), normal seedling percentage (Fig 4), seedling length (Fig 5) and the minimum mean time to germination (Fig 3) were attained from as osmo-priming in control conditions. Therefore, our results showed that increases drought stress, lead to growth reduction. Ansari et al. (2012) reported that increases drought stress lead to growth reduction. Ansari and Sharif Zadeh (2012) reported that drought stress lead to reduction of growth and plant developments. Also, the results are in agreement with the earlier study who reported that the significant reduction in the germination as well as growth of other crops under drought stress (Okçu et al., 2005; Ansari et al., 2012; Soltani et al., 2006), also reported that priming increased germination percentage under drought stress. Seed priming techniques have been used to increase germination, improve germination uniformity, improve seedling establishment and stimulate vegetative growth in more field crops such as: wheat (Iqbal and Ashraf, 2007; Soltani et al., 2006), sunflower seeds (Kaya et al, 2006), Chickpea (Kaur et al, 2002) and mountain rye (Ansari et al., 2012) under stressed conditions.

Results showed that priming increases weight of utilized (mobilized) seed reserve and seedling dry

weight as compared to the unprimed seeds under drought stress (Fig 6 and 7). Also, other researchers reported that priming increased weight of utilized (mobilized) seed reserve and seedling dry weight as compared to unprimed seed also this traits decline under stress conditions (Ansari et al., 2012; Soltani et al., 2006).

Other our results showed that the highest seed reserve utilization efficiency obtained from unprimed in –8 bar osmotic pressure condition (Fig 8), but in higher levels of osmotic pressures the highest seed reserve utilization efficiency was attained from osmo and hormone priming (Fig 8). Thus priming lead to improvement in mentioned traits in millet seeds under drought stress.

These results agree whit those of Ansari et al. (2012) and Soltani et al. (2006). Decline in seed reserve utilization efficiency to stress conditions were also reported by other researchers (Soltani et al., 2006; Sadghi et al., 2011; Ansari et al., 2012). Decline in seedling growth and different indices of seeds under stress conditions also reported for wheat (Soltani et al., 2006), tomato (Bhatt and Srinivasa-Rao, 1987), mountain rye (Ansari et al., 2012; Ansari and Sharif Zadeh, 2012) and mung bean (De and Kar, 1995).

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Figure 2 : The effect of priming on germination index of millet seeds under drought stress.

Figure 3 : The effect of priming on mean time to germination of millet seeds under drought stress.

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Figure 5 : The effect of priming on seedling length of millet seeds under drought stress.

Figure 6 : The effect of priming on weight of utilized seed reserve of millet seeds under drought stress.

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Figure 8 : The effect of priming on seed reserve utilization efficiency of millet seeds under drought stress.

CONCLUSION

Priming by PEG 6000 and salicylic acid increased germination characteristics as compared to the unprimed seeds. The highest germination characteristics were obtained from priming by PEG 6000 and salicylic acid in control conditions. Priming improved seed reserve utilization such as: weight of utilized (mobilized) seed reserve, seed reserve utilization efficiency and seedling growth in millet seedsunder stress and control conditions.

REFERENCES

Almansouri, M., Kinet, J.M., and Lutts, S. (2001) Effect of salt and osmotic stresses on germination in durum wheat (Triticum durum Desf.). Plant and Soil. 231: 243-254.

Ansari, O., Azadi, M.S., Sharif-Zadeh, F., and Younesi, E. (2013) Effect of hormone priming on germination characteristics and enzyme activity of mountain rye (Secale montanum) seeds under drought stress conditions. Journal of Stress Physiology and Biochemistry. 9 (3): 61-71.

Ansari, O., Choghazardi, H.R., Sharif Zadeh, F., and Nazarli, H. 2012. Seed reserve utilization and seedling growth of treated seeds of mountain ray (Seecale montanum) as affected by drought

stress. Cercetări Agronomice în Moldova. 2 (150): 43- 48.

Ansari, O., and Sharif-Zadeh, F. (2012) Osmo and hydro priming improvement germination characteristics and enzyme activity of Mountain Rye (Secale montanum) seeds under drought stress. Journal of Stress Physiology and Biochemistry. 8 (4): 253- 261.

Bajehbaj, A.A. (2010) The effects of NaCl priming on salt tolerance in sunflower germination and seedling grown under salinity conditions. African Journal of Biotechnology. 9: 1764-1770.

Bhatt, R.M., and Srinivasa-Rao, N.K. (1987) Seed germination and seedling growth responses of tomato cultivars to imposed water stress. J. Hort. Sci. 62: 221–225.

De, R., Kar, P. (1995) Seed germination and seedling growth of mung bean (Vigna radiata) under water stress induced by PEG-6000. Seed Sci. Technol. 23: 301–308.

Iqbal, M., and Ashraf, M. (2007) Seed treatment with auxins modulates growth and ion partitioning in saltstressed wheat plants. J Integr Plant Biol. 49: 1003-1015.

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seedling growth and carbohydrate metabolism water deficit stress. Plant growth Regul. 37: 17-22.

Kaya, M.D., Okcu, G., Atak, M., Cikili, Y., and Kolsarici, O. (2006) Seed treatments to overcome salt and drought stress during germination in sunflower (Helianthus annuus L.). Eur J Agro.24: 291-295.

Okçu, G., Kaya, M.D., and Atak, M. (2005) Effect of salt and drought stresses on germination and seedling growth of pea (Pisum sativum L.). Turk j Agric For. 29: 237- 242.

Rouhi, H.R., Aboutalebian, M.A., Moosavi, S.A., Karimi, F.A., Karimi, F., Saman, M., and Samadi,

M. (2012) Changein several antioxidant enzymes activity of Berseem clover (Trifolium alexandrinum L.) by priming. International Journal of AgriScience. 2(3): 237-243.

Sadeghi, H., Khazaei, F., Yari, L., and Sheidaei, S. (2011) Effect of seed osmopriming on seed germination behavior and vigor of soybean (Glycine max L.). ARPN Journal of Agricultural and Biological Science: 6(1).

Soltani, A., Gholipoor, M., and Zeinali, E. (2006)

Seed reserve utilization and seedling growth of

wheat as affected by drought and salinity.

Environmental and Experimental Botany. 55:

Imagem

Figure 1 : The effect of priming on germination percentage of millet seeds under drought stress.
Figure 3 : The effect of priming on mean time to germination of millet seeds under drought stress.
Figure 5 : The effect of priming on seedling length of millet seeds under drought stress.
Figure 8 : The effect of priming on seed reserve utilization efficiency of millet seeds under drought stress.

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